We are excited to announce that Amazon ElastiCache now supports enhanced Redis Backup and Restore with Cluster Resizing. In October 2016, we launched support for Redis Cluster with Redis 3.2.4. In addition to scaling your Redis workloads across up to 15 shards with 3.5TiB of data, it also allowed creating cluster-level backups, which contain snapshots of each of the cluster’s shards. With this launch, we are adding the capability to restore a backup into a Redis Cluster with a different number of shards and slot distribution, allowing you to resize your Redis workload. ElastiCache will parse the Redis key space across the backup’s individual snapshots, and redistribute the keys in the new Cluster according to the requested number of shards and hash slots. Your new cluster can be either larger or smaller in size, as long as the data fits in the selected configuration.
Enhanced Backup and Restore with Cluster Resizing also provides an easy migration path to a managed Redis Cluster experience on ElastiCache. If you are running self-managed Redis on EC2, you can take RDB snapshots or your existing workloads (both Redis Cluster and single-shard Redis) and store them in S3. Then simply provide them as input for creating a sharded Redis Cluster on ElastiCache, and the desired number of shards. ElastiCache will do the rest.